1. Field of the Invention
This invention relates in general to semiconductor devices and in particular to transistors with vertical structures.
2. Description of the Related Art
Some memories such as e.g. flash memories or other types of non volatile RAM utilize a floating gate structure of a transistor for storing charge indicative of a value being stored in a memory cell being implemented with the transistor. The ratio of the capacitance between a control gate and a floating gate of a transistor to the capacitance between the floating gate and a channel region of the transistor affects the ability to read and write to a memory cell implemented with the transistor. Typically, it is desirable to have a larger capacitance between the control gate and the floating gate than between the floating gate and the channel region.
The use of the same reference symbols in different drawings indicates identical items unless otherwise noted. The figures are not necessarily drawn to scale.